Specify a database connection on a per-model basis by declaring instance variable

README.md

@@ -315,14 +315,14 @@ Database Connection
 
 The class will automatically use the default database connection, and even load it for you if you haven't yet.
 
-You can specify a database connection on a per-model basis by declaring the _$\_db\_group_ instance variable. This is equivalent to calling `$this->db->database($this->_db_group, TRUE)`.
+You can specify a database connection on a per-model basis by declaring the _$\_database_ instance variable. This is equivalent to calling `$this->db->database($this->_database, TRUE)`.
 
 See ["Connecting to your Database"](http://ellislab.com/codeigniter/user-guide/database/connecting.html) for more information.
 
 ```php
 class Post_model extends MY_Model
 {
-    public $_db_group = 'group_name';
+    public $_database = 'group_name';
 }
 ```
 

core/MY_Model.php

@@ -21,8 +21,8 @@ class MY_Model extends CI_Model
     protected $_table;
 
     /**
-     * The database connection object. Will be set to the default
-     * connection. This allows individual models to use different DBs
+     * The database connection object. Will be set to the default group
+     * connection. This allows individual models to use different DB groups
      * without overwriting CI's global $this->db connection.
      */
     public $_database;
@@ -105,6 +105,9 @@ public function __construct()
 
         $this->_fetch_table();
 
+        if($this->_database){
+            $this->db = $this->load->database($this->_database, TRUE);
+        }
         $this->_database = $this->db;
 
         array_unshift($this->before_create, 'protect_attributes');
@@ -760,6 +763,27 @@ public function order_by($criteria, $order = 'ASC')
         return $this;
     }
 
+    /* --------------------------------------------------------------
+     * QUERY BUILDER DIRECT ACCESS METHODS
+     * ------------------------------------------------------------ */
+    /**
+     * A wrapper to $this->_database->group_by()
+     */
+    public function group_by($criteria)
+    {
+        if ( is_array($criteria) )
+        {
+            foreach ($criteria as $key => $value)
+            {
+                $this->_database->group_by($value);
+            }
+        }
+        else
+        {
+            $this->_database->group_by($criteria);
+        }
+        return $this;
+    }
     /**
      * A wrapper to $this->_database->limit()
      */